Delta is offering $200 travel vouchers to customers whose flights have been delayed more than three hours or canceled through 12 p.m. Wednesday.
Delta spokesman Trebor Banstetter said that after Monday's power outage, key systems and network equipment did not switch over to backups. The investigation of the outage is ongoing, but Banstetter said that there is no indication that the problems were caused by a hack or intentional breach of the system.
Delta is based in Atlanta.
A spokesman for the local electric company, Georgia Power, said the problem started with a piece of Delta equipment called a switchgear, which direct flows within a power system. No other customers lost power, he said.
The Associated Press contributed to this report.